中太平洋铁锰结壳铅同位素研究  

RESEARCH OF LEAD ISOTOPE OF FERROMANGANESE CRUSTS FROM CENTRAL PACIFIC OCEAN

作　　者：周枫[1] 凌洪飞[1] 陆尊礼[1] 蒋少涌[1] 

机构地区：[1]南京大学成矿机制研究国家重点实验室,南京210093

出　　处：《海洋地质与第四纪地质》2005年第1期55-62,共8页Marine Geology & Quaternary Geology

基　　金：国家自然科学基金项目(49873003);大洋协会国际海域研究开发"十五"计划(DY105 01 04 6)

摘　　要：已有研究表明大洋中溶解的铅(Pb)来源于陆源物质,但是,对 Pb进入大洋的途径争议很大。为此分析了取自中太平洋两块铁锰结壳样品的Pb同位素组成,获得了整个新生代的中太平洋Pb同位素演化历史。结果表明这两块结壳的Pb同位素随时间的演化曲线与中北太平洋沉积物岩心LL44 GPC3中风成碎屑的Pb同位素演化曲线相似。证实该区深水中的天然溶解铅主要来自风成粉尘,并且 50 Ma之前中太平洋中溶解 Pb同位素组成主要取决于源自美洲的风成粉尘的输入,40 Ma之后主要取决于源自亚洲的风成粉尘的输入。Previous studies have shown that terrigenous sources have controlled dissolved oceanic lead (Pb). However, the pathways of terrigenous Pb input into the ocean are highly controversial. Here we present Pb isotopes of two ferromanganese crusts from Central Pacific, and obtain Pb isotope time series over the Cenozoic period in Central Pacific Ocean. The lead isotope evolution of the crusts are similar to that of core GPC3, which is also from the north Central Pacific. Our data suggest that eolian dust has been a major contributor to dissolved Pb in Central Pacific deep water. Prior to 50 Ma American continental eolian dust was the main contributor to the Pacific Pb, which was controlled by Asian eolian dust since 40 Ma.

关 键 词：中太平洋 PB同位素 铁锰结壳 大洋 铅同位素 陆源物质 演化历史 粉尘 沉积物 溶解 

分 类 号：P736[天文地球—海洋地质] P744[天文地球—海洋科学]